In network systems where data for various types of processing (hereinafter, also referred to as message) is transmitted among many communication nodes, desirably all of messages transmitted are stored for analysis of the cause of a communication error. Storing all messages is difficult because, while numerous messages are transmitted in such systems, memories in the communication nodes have a limited capacity.
Japan Patent JP 10-190778 A, for example, discloses a method of logging communication errors. However, this method updates the communication error log by overwriting, and no record of the fact that there has been a communication error remains when the communication error log is overwritten after a lapse of some time.
The website, http://e-words.jp/, for example, discloses a Java (Registered Trademark) virtual machine. Memory management of this Java virtual machine allows one allocating a storage area to set whether to free up the storage area when the remaining memory capacity becomes small.